Regenerator matrix



Nov. 18, 1969 H. E. HELMS REGENERATOR MATRIX Filed Feb. 19, 1968 W wzsa? ATTORNEY United States Patent M 3,478,816 REGENERATOR MATRIX Harold E. Helms, Indianapolis, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Feb. 19, 1968, Ser. No. 706,504

Int. Cl. F28f 19/04 US. Cl. 165-9 6 Claims ABSTRACT OF THE DISCLOSURE A radial-flow regenerator matrix has two coaxial rims between which is mounted a body of heat transfer material pervious to flow radially through the body between the rims. The heat transfer material is defined by flat and corrugated plates which provide separate passages generally parallel to the inner surfaces of the rims. These passages are blocked adjacent the rim to provide a dead air zone and so that the layers of heat transfer material nearest the rim act as a heat block between the hot portions of the matrix and the rim to minimize temperature gradients in the rim.

The invention herein described was made in the course of work under a contract or subcontract thereunder with the Department of Defense. My invention is directed to the improvement of regenerators which, in their usual form, are devices in which an annular heat transfer mass is slowly rotated through two chambers in a housing, with a distinct fluid flowing through the matrix in each of the two chambers so that heat is extracted from one fluid by the matrix and delivered to the other fluid.

For good effectiveness, the flow in such matrices is counterflow, which means that one of the faces through which fluid enters and departs is much hotter than the other. This temperature differential may in some cases be as much as 500 F. The heat transfer material of the usual matrix is mounted between two rims which are ordinarily coaxial, and may be concentric. This high temperature gradient is communicated in large extent to the rim which usually is a solid metal body of considerable thickness. Stresses developed in the rims because of the temperature gradient in some cases have led to premature failure of the rims.

In many cases, the heat transfer material of the matrix is made up of sheets or layers which guide the flow from face to face of the matrix indistinct paths generally parallel to the inner or mutually facing surfaces of the rim. This is the case in a radial-flow matrix in which the heat transfer material comprises generally radial plates or sheets as in the structure described in US. Patent No. 3,373,798 or in the structure described in Hess US. Patent No. 2,978,277. It is also the case in axial-flow matrices in which the heat transfer material is formed by spiral windings of metal strips, or the equivalent.

My invention is based upon the observation that, in a matrix having such structure that the flow is guided generally parallel to the rims and cannot flow at random, the rim may be isolated from the flow and provided with a very considerable measure of insulation from the hot gases and from the temperature gradients in the active part of the matrix by the simple expedient of plugging or blocking flow paths through the matrix immediately adjacent the rim. The temperature gradient in the rim is thus greatly reduced, and failures because of temperature gradient induced stresses are prevented.

The principal object of my invention is to improve the performance and reliability of rotary regenerators. A further object is to reduce thermal stresses in the rims of the matrices of such regenerators.

3,478,816 Patented Nov. 18, 1969 The nature of my invention and the advantages thereof will be more fully apparent from the succeeding detailed description of a preferred embodiment thereof and the accompanying drawings.

FIGURE 1 is a somewhat schematic representation of a radial-flow regenerator.

FIGURE 2 is a fragmentary sectional view through the matrix taken in a plane containing the axis thereof, as indicated by the line 2-2 in FIGURE 1.

FIGURE 3 is a fragmentary plan view of the radially outer surface of the matrix.

FIGURE 1 illustrates a regenerator having a matrix of the sort described in Patent No. 3,368,612 or Patent No. 2,978,277 referred to above, and provided with main seals of the type described in Brummett Patent No. 3,368,612.

Referring first to FIGURE 1, a conventional radialflow rotary regenerator may include a suitable housing 7 divided by a fixed bulkhead 8 into two chambers or flow paths, one for each of two fluids. As illustrated, a first fluid, which may be air delivered by the compressor of a gas turbine, enters the housing at an inlet 9, flows inward through the leftward portion, as illustrated, of a matrix 11, and is discharged through an outlet 13. The other fluid which may be exhaust gas from a turbine, enters the housing through an inlet 14 and flows radially outward through the rightward portion of the matrix, as illustrated, to an outlet 15. The matrix 11 is slowly rotated about its axis indicated at 17. It may be supported and driven by any suitable structure such as rollers 18 which engage the rims 20 at each end of the drum-shaped matrix. The matrix passes through openings 21 in the bulkhead 8 where leakage of fluid from one side of the bulkhead to the other is minimized by suitable main seals 22 which, as illustrated, are of the type described in Patent No. 3,368, 612. The particular structure of the seals is immaterial to the present invention. Such a regenerator also ordinarily includes rim or by-pass seals 24 one of which is indicated in broken lines in FIGURE 1 and the other of which would lie against the face of the near rim 20 and therefore is not shown. Such a rim seal 24 is also indicated fragmentarily in FIGURE 2. The rim seal in a radial-flow matrix usually engages the outer or radial face of the rim but not necessarily so. By-pass seals are shown in United States Patents Nos. 3,077,074 and 3,360,275. The heat transfer material mounted between the rims 20 may be of any type which allows flow generally parallel to the rims rather than random flow. The preferred configuration of the porous heat transfer material 25 is described fully in Patent No. 3,373,798 referred to above. Such material may comprise sheets which are provided with zigzag corrugations so that the corrugations space the sheets to provide the flow paths and also cause turbulence in the flow. However, for clarity of illustration in connection with this invention, the matrix is depicted as one in which the heat transfer material is made up of alternating flat and corrugated sheets, another well-known configuration. Thus, as shown in FIGURES 2 and 3, the matrix is made of alternating corrugated sheets 26 and flat sheets 27. The sheets may be rings as in Hess Patent No. 2,978,227. It is more feasible to depict my invention clearly by showing the structure of the Hess patent rather than that of the Brummett patent. However, my invention is equally applicable to both structures.

To convert a prior art matrix, whether that of the Hess patent, that of the Brummett patent, or other matrices, including axial-flow ones, into a matrix embodying my invention, it is only necessary to close, through the entire circumference, at least one and preferably several of [the sets of flow paths between pairs of sheets adjacent to the rims. Thus, as illustrated in FIGURES 2 and 3, flow through the matrix is blocked from the rim to the third flat sheet 27 from it, thus blocking all six sets of flow paths between the rim and the sixth nearest heat transfer sheet.

This blockage is most easily accomplished by filling the passages with some material which will not melt at the temperatures encountered. As shown in FIGURES 2 and 3, the-spaces between the heat transfer sheets are plugged by braze metal 30 which is disposed to fill the passages adjacent the outer or cooler face of the matrix. While the plug could be at some other location radially of the matrix, it is most feasible to put it at a face, and also at the cooler face. It will be seen that, with the flow blocked adjacent the rims, there are a number of heat shields or heat dams defined by sheets 26 and 27 between the rim 20 and the nearest active flow path through the matrix, which is indicated by the arrow 32.

Obviously, many means may be adopted to block the desired number of flow paths adjacent the rim.

Tests have shown a reduction of eighty percent in the temperature gradient of a matrix rim of the type descried in the Brummett application upon plugging the passages as described herein.

The detailed description-of the preferred embodiment of the invention for the purpose of explaining the principles thereof is not to be considered as limiting the invention, since many modifications may be made by the exercise of skill in the art.

I claim:

1. A regenerator for heat exchange between two flowing fluids comprising, in combination, a housing including means dividing the housing into two chambers and providing a fluid path through each chamber for one of the two fluids; a flow-permeable heat-storing matrix; means operable to move the matrix so as to dispose each element of the matrix alternately in the flow path of each fluid; the matrix including two annular rims defining the edges of the matrix and flow-permeable heat storage and transfer material supported by the rims and mounted between the inner surfaces of the rims; the matrix having two faces and the flow-permeable material defining a flow path for the said fluids from face to face of the matrix, the said rims also extending from face to face and being impervious to fluid flow between the faces; by-pass seal means engaging the said rims to direct fluid flow through the matrix and effective to lock flow of the said fluids from face to face of the matrix over the outer surfaces of said rims; the matrix being characterized by means for minimizing temperature gradients in the rims in the direction from face to face of the matrix by blocking flow of the said fluids from face to face over the inner surface of each rim, the said means comprising a plurality of sheets extending generally parallel to the inner surface of the rim interposed between each rim and the flow-permeable material and defining spaces between the sheets, and barrier means blocking flow of the said fluids from face to face between the said sheets and between the sheets and the adjacent rim,

2. A regenerator as defined in claim 1 in which the barrier means is a metal filling bonded to the matrix.

3. A regenerator as defined in claim 1 in which the barrier means is at the cooler face of the matrix.

4. A regenerator as recited in claim 1 in which the flow-permeable material is made up of sheets generally parallel to the inner surfaces of the rims.

5. A regenerator as defined in claim 1 in which the flow is radial and the said faces are the inner and outer face.

6. A radial-flow regenerator for heat exchange between two flowing fluids comprising, in combination, a housing including means dividing the housing into two chambers and providing a fluid path through each chamber for one of the two fluids; a flow-permeable heat-storing matrix; means operable to move the matrix so as to dispose each element of the matrix alternately in the flow path of each fluid; the matrix including two coaxial rims defining the ends of the matrix and a multiplicity of rings of sheet material stacked between and supported by the rims, the rings being supported by the rims and mounted between the inner surfaces of the rims configured so as to define radial flow paths through the matrix generally parallel to the inner surfaces of the rims; the matrix having two faces and the flow-permeable material defining a flow path for the said fluids from face to face of the matrix, the said rims also extending from face to face and being impervious to fluid flow between the faces; by-pass seal means engaging the said rims to direct fluid flow through the matrix and effective to block flow of the said fluids from face to face over the outer surfaces of said rims; the matrix being characterized by means for minimizing temperature gradients in the rims in the direction from face to face of the matrix comprising a plurality of said rings of sheet material adjacent each rim and means bonded to the said plurality of rings and the rims blocking flow through the flow paths defined by the said plurality of rings and the rim.

References Cited UNITED STATES PATENTS 2,937,010 5/1960 Collman et a1. 10 3,162,241 12/1964 Smith 1659 3,216,487 11/1965 Gallagher 165-9 3,242,977 3/1966 Cobb 16510 3,368,612 2/1968 Brummett 165--9 3,392,776 7/1968 Topouzian 165-10 X ROBERT A. OLEARY, Primary Examiner ALBERT W. DAVIS, Assistant Examiner U.S. Cl. X.R.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 a Dated November 18, 1.969

Inventor(s) Harold lms It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Colman 4, line a, "claim 1" should read claim 2 SIGNED AND SEALED APR 2 81970 (SEAL) Aueat:

Edward M. Fletcher, 1!. WILLIAM E 5am m I I Anesfing Officcr Coxmnissioner of Patents 

